This invention relates to a key lock apparatus and particularly to a key lock switch apparatus incorporating a low-cost key lock structure.
In many applications, a key switch unit for controlling an electrical circuit is required. In many instances, the cost factor is of substantial significance and the lock structure need not include a complex high security system such as provided by conventional tumbler locks corporated into various door locks, keyed ignition switches for automobiles and the like. Typical applications for low level security key actuated start switches include small lawn equipment, such as lawn tractors, mowers and the like. Other applications would include small motor driven boats, various storage cabinets and the like. A common switch structure used in low security systems include a simple rectangular switch opening having an internal edge surface for restricting actuation of the switch unit to a flat key having a corresponding simple offset edge surface. The key is a simple, flat stamped key structure, generally having a lateral groove or offset with a corresponding notched key to further restrict insertion of a flat member into the key slot for actuation of the key lock structure. With present day low security lock structures, a pin or flat metal member can often be introduced into the key lock for actuating of the key lock structure, thereby effectively eliminating the security factor. Further, the keys are often retained in the lock structure by the frictional engagement of key and internal lock structure. Although in many applications such low cost structures are acceptable, the vibration in the tractor structure may cause the key to actually move from the key lock.
There is therefore a need for a simple but reliable low cost key lock assembly for retaining of the key within the lock with a requirement for positive removal as well as preventing actuation of the key lock unit with a simple inserted plate-like member or the like.